ionic app build fails with error 'linker command failed with exit code 1 (use -v to see invocation)'
The Xcode error linker command failed with exit code 1 (use -v to see invocation)
led me to this stack overflow answer
The second answer there suggests a check for multiple / duplicate .m files in the Xcode project Compile Resources:
That can happen if the same .m file is referenced multiple times in your target's "Compile Sources" section in "Build Phases". Remove duplicate entries and you should be fine.
So I had a check in Xcode and there was indeed a duplicate call to a plugin resource.
After checking package.json I found the same plugin was referenced in two ways (with two paths).
Removing one of the two plugins resolved the issue.
I found the solution on github
the solution for me was open the .xcworkspace file insted of .xcodeproj located inside my '/platforms/ios' folder.
https://github.com/phonegap/phonegap-plugin-push/issues/1240